Carburetor



Fig.1.

H. G. DUNCAN.

CARBURETOR. APPLlCATl0N FlLED SEPT. I8. 1919.

Patented Apr. 18, 1922.

f Willi/ 017191121 yllllllllllllll/a /ll HERBERT GERRARD DUNCAN,

I CARBURETOR.

Specification of Letters Patent. Patented Apr, 18, 192,).

Application filed September 18, 1919. Serial No. 324,445.

To all whom it may conccm:

Be it known that I, HERBERT GERRARD DUNCAN, of 1 Southwoods, Yeovil, in the county of Somerset, England, a subject of the King of Great Britain and Ireland, have invented certain new and useful Improvements in Carburetors, of which the followin is a specification.

his invention relates to carburetors for internal combustion engines, the principal object .of the invention being to provide an improved carburetor for internal combustion engines operating on the two-cycle principle whereby a more complete atomization of the fuel is accomplished than was heretofore ossible.

A rtherv object of the invention is the pro vision of a carburetor inwhich the delivery orifices of the, fuel andiair nozzles or jets are located in close contact and approximately at right angles to eachother, whereby the fuel is led out of the delivery end of the fuel nozzle and into the delivery end of the air nozzle by the induction action of the flow of air through the air nozzle, the fuel being immediately broken up into a fine spray.

A still further object of the invention is the provision of a carburetor in which the air nozzle is provided with an enlargement or venturi whereby the depression about the neck of said venturi increases the velocity of the airover and immediately around the fuel nozzle, thereby causing the flow of the fuel by induced currents of air.

With the'foregoing and other objects in view, which will appear as the description proceeds, the invention consists in the novel features of construction and combination of parts which will be more fully described hereinafter and particularly pointed out in the claim.

In-the drawings accompanying and form ing part of this specification,

igure 1 is a central vertical section of a portion of the cylinder wall of a two-cycle combustion engine, and illustrating a nozzle constructed in accordance with the present invention; and

Figs. 2 and 3 are end views of said nozzle looking respectively in the direction of the arrows Y and z of Fig. 1.

The same characters of reference designate the same parts in the different figures of the drawings.

Referring to the drawings, the fuel nozzle consists of a tube d which is closed at its delivery end as shown at 0, but is provided immediately-back of the wall 0 with a plurality of radially extending ports or nozzles f in communication with its longitudinal passageway. The air nozzlel comprises a member Z), the exterior form of which is substantially conical and having its receiving end 6 so formed as to present almost a knife edge to the rush of air; The air nozzle 6 encircles the fuel nozzle (Z and is provided at its delivery end with a plurality of approximately semi-circular openings 6, one for each of the radial ports of the fuel nozzle, the delivery end of said ports being disposed'within said openings, the end wall of the air nozzle between said openings engaging the periphery of thefuel nozzle (Z between the ports 7, as shown in Figs. 2 and 3.

From thisconstruction it will be seen that the openings 6 in the air nozzle completely envelop the outlet ends of the ports f of the fuel nozzle.

By means of the construction above described, air is trapped in the venturi g of the combined nozzle, and owing to the fact that the air passage is of smaller diameter as it approaches its delivery end, the air that flows around the fuel ports f has its velocity considerably increased. The effect of this increased velocity is to cause a depression of the air about the fuel ports which induces a flow of fuel and at the same time atomizes itso that a thorough mixture of the air and fuel takes place just prior to their delivery into the cylinder of the en- 0'1116.

a WVhile I have described in detail the structure herein illustrated, ibis to be understood that I do not thereby limit my invention to the precise features of construction shown, asI am aware that many mechanical changes and modifications maybe made therein withor YEovIL, ENG-LAND, nssrsnon r'o 'rn'rrnns mnirnn, -.or YEOVIL, ENGLAND.

nozzle having an axially extending passageway and a plurality of radially extend-o ing ports in communication with said pas-- sageway,'and an air nozzle having an en larged and outwardly flared passageway at its receiving end, said passageway merging into a plurality of restricted outlets at HERBERT GEBRARD DUNCAN. 

